A known folding stamp has a web extending in a longitudinal direction, a base plate fastened to the web, and a plate on the web forming a resting surface. A fastening unit connects the folding stamp to other equipment in the sewing system. Guide plates are arranged on both sides of the web at its front end for guiding workpieces into the folding stamp.
In the DURKOPP Class 746 sewing system which is used for the production of piped pockets, a gripping/folding stamp is used, by which a strip of piping is automatically placed on the main part of the material being sewn, in an application station associated with the sewing machine, and the piping strip can be folded around the gripping/folding stamp. The attachment parts such as flaps, trimming and pocket-bag blanks are applied by hand to the gripping/folding stamp. In order to simplify this operation for the operator, this gripping/folding stamp is provided with a so-called resting surface which is formed by a plate which closes off the top of the web and widens it.
Since this gripping/folding stamp has to carry out a swinging motion (in order to grip and feed the strip of piping) and a vertical motion (in order to position the strip of piping) it is connected to the sewing machine via a fastening unit which is fastened to its web approximately at the center along its length. The resting surface is arranged behind the fastening unit as seen from the direction of the sewing station. The resting surface formed on the gripping/folding stamp must be sufficiently long for the work pieces which are to be placed on it to be suitably aligned. The gripping/folding stamp of the prior art is therefore relatively long.
The transport path of the workpieces to be sewn together, from the feed station into the sewing station, depends on the length of the gripping/folding stamp. The longer this path, the greater the corresponding cycle time of the sewing machine.
Federal Republic of Germany 38 34 434 C2 (corresponding to U.S. Pat. No. 5,092,258) (Goldbeck et al.) discloses a gripping/folding stamp which is used in a sewing system in which the strip of piping and the flap and/or the pocket-bag blank are automatically fed. Since the feeding and folding involve purely automatic movements and can be reproduced at any time, the gripping/folding stamp can be made correspondingly short in order to decrease the cycle time. That is, the aligning of the workpieces is effected on the feed tables, and not on the gripping/folding stamp itself. For this reason, the gripping/folding stamp can be of relatively simple construction. Since it does not have a resting surface which widens the web, manual feeding of the flap and/or the pocket-bag blank is not possible, except in a very time-consuming manner, if at all.